[llvm] [VectorCombine] foldShuffleOfBinops - fold shuffle(binop(shuffle(x),shuffle(z)),binop(shuffle(y),shuffle(w)) -> binop(shuffle(x,z),shuffle(y,w)) (PR #120984)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

> @RKSimon It looks like [af83093](https://github.com/llvm/llvm-project/commit/af83093933ca73bc82c33130f8bda9f1ae54aae2) causes an llvm-test-suite hang in ReleaseLTO-g configuration.

I'll revert - I'm still on holiday break and don't have much time to look at this right now.

https://github.com/llvm/llvm-project/pull/120984